Soil properties and yields of winter wheat after long-term growing of this crop in two contrasting rotations

This study was based on a long-term field experiment established in 1967 in which winter wheat is grown in two rotations consisting of: potato-winter wheat-fodder crops-winter wheat (rotation A) and oat-winter wheat-winter rye-winter wheat (rotation B). In the years 2010- 2013 selected soil properties and winter wheat yields as influenced by these rotations were analysed. The soils under winter wheat grown in crop rotations A and B contained similar amounts of total organic carbon (C) (0.76% and 0.80%, respectively) and did not differ significantly with respect to biological characteristics (contents of microbial biomass C and nitrogen (N), dehydrogenase and acid phosphatase activities). Averaged for 3 years, the highest grain yields were obtained for winter wheat grown after potato in rotation A (7.94 t/ha) and the lowest (6.0 t/ha) for wheat following winter rye in rotation B. The highest take-all index and the lowest numbers of ears/m(2) were the main factors influencing poor performance of winter wheat following rye.